The invention relates to a test element for generating a puncture wound in a body part, for receiving a body fluid from the body part, and for analyzing the body fluid for an analyte contained therein. A method for producing the test element and an analysis system, which includes a test element according to the invention and a specially adapted evaluation device capable of evaluating it, are also the object of the invention.
Such test elements and analysis systems are primarily used for medical analyses. They is are common in numerous variants for the quantitative and qualitative determination of different analytes. Systems for determining the glucose concentration in the blood of diabetics have particularly great medical and economic significance. The invention is particularly suitable for such systems. However, it is not restricted thereto. Another important analyte is cholesterol, for example.
The invention is particularly directed to applications in which the analysis is performed by the patient himself, in order to monitor his health status (“home monitoring”). Simple handling is particularly important in this case. In addition, the evaluation devices must be as small, light, and robust as possible.
The sample required for the analysis is typically obtained by a puncture in the finger or in another body part. The sample liquid is blood and/or interstitial liquid, blood being referred to hereafter without restriction of the generality. In the analysis systems which are still currently predominantly typical, separate instruments are used for the sample acquisition and the analysis, namely a lancet device for generating a wound in a body part, from which blood exits, and analysis elements, for example, in the form of test strips, which are manually brought into contact with the blood exiting from the wound and subsequently evaluated by means of a device associated with the analysis system. This requires multiple handling steps: puncture in the finger, manipulation of the skin surface to encourage the blood exit, contacting the test strip with the blood droplet, and evaluation by means of the device. These handling steps are not only time-consuming and unpleasant, but rather also difficult to perform for many patients, who are typically older and/or impaired by illness.
In order to overcome these problems, analysis systems have been proposed, in which all steps required for the performance of the analysis, from the puncture in the finger up to the display of the analytical result, run completely automatically, without the user having to perform further handling steps after the puncture. Such systems are also designated as “G&M-systems” in the English-language literature, because they allow the sample to be obtained (“G” for “get”) and the analytical value to be measured (“M”). Most G&M-systems operate with test elements which have both a puncture element and also an element necessary for the performance of the analysis as integral components. The two components of the test elements (puncture element and analysis element) are typically already assembled into a test element at the producer. However, there are also G&M-systems in which the analysis element and the puncture element are first brought is together in the device in such a manner that a contact is produced between both elements, which allows the transfer of sample liquid from the puncture element to the analysis element and which is designated as “fluid contact”.
G&M-systems are described, for example, in the following publications:
(1) WO 01/72220
(2) WO 03/009759
(3) EP 1 360 931 A1
(4) EP 1 360 933 A1
(5) WO 2005/084546
(6) WO 2006/105968
(7) WO 2007/045412
The function of the test systems is decisively influenced by the properties of the test elements used therein. They are to meet an array of difficult and partially contradictory requirements. On the one hand, a high analysis precision is to be achieved. On the other hand, the design is to be as simple as possible and is to allow cost-effective manufacturing. In order to house as many test elements as possible in a device, they are to be as small as possible. A requirement for rapid and reliable analysis is that only a very small sample volume, typically less than 1 μL, is necessary. Finally, the test elements and the associated evaluation devices must be robust enough to ensure reliable function in everyday operation.